Three crosslinked copolymer nanospheres were prepared by inverse microemulsion polymerization. Resistance temperature and resistance salinity of the copolymer CP(AM-AA-AMPS) [crosslinked poly(acrylamide-acrylic acid-2-acrylamide-2-methylacrylic sulfonic acid)] nano-spheres were superior to the CPAM (crosslinked polyacrylamide) nano-spheres and CP(AM-AA) [crosslinked poly(acrylamide-acrylic acid)] nano-spheres. The nanospheres had a tendency to plug the high-permeability layer and drive crude oil from the low-permeability layer. Meanwhile, these nanospheres displaced crude oil that existed in the pores or throats when they were conveyed in porous media. Consequently, deep profile control and oil displacement could be entirely actualized, and the ultimate goal of enhanced oil recovery could be achieved for high-temperature and high-salinity reservoirs.